The recent Teagasc ‘Soils Day’ attracted a large turnout of farmers from across the country to Johnstown Castle in Co. Wexford.
The event was held directly in the wake of the third global soil biodiversity conference, which had been jointly hosted by Teagasc and University College Dublin (UCD).
According to Teagasc’s Dr. David Wall, managing soil health will be a critically important objective for farmers and all land users into the future.
He added that the care of soils will have a fundamental impact on how we produce food and manage our environment.
Health of soils
His colleague Dr. Lilian O’ Sullivan discussed the various factors that come into play when determining the actual health of a soil.
She confirmed that soil health can be discerned in terms of a soil’s continuing capacity to function as a living ecosystem – one that is capable of sustaining plants, animal and humans.
“It’s important that soils are healthy now and into the future,” O’Sullivan said.
“We want them to function as living eco systems. Historically, our sole focus has been on the productive capacity of our land. In other words, the ability of our soils to produce food, fibre and raw materials like timber.
“And this will be important going forward. But as we look to the future, our soils will be expected to perform a number of other roles.”
O’Sullivan specifically highlighted the role of soils to recycle nutrients. She said that it is important to ensure that the nutrient recycling capacity of the soil is maximised.
If this is not being achieved, the end result will be the escape of greenhouse gases (GHGs) to the atmosphere.
Clean water
According to O’Sullivan, healthy soils also play an important role in purifying water. But, again, this comes back to the fundamental requirement of managing the recycling of nutrients within it effectively.
“We all need clean water. So it is important that our soils are managed in ways that makes this happen,” O’Sullivan continued.
“Different soils have different water-holding capacities. And this facet of a soil is important when it comes to determining its ability to successfully grow crops.
“Soil structure is particularly important. Soils also represent a habitat for so many plants and animals. They represent the engine form of biodiversity.”
O’Sullivan went on to highlight the carbon sequestration and storage capacity of soils and the growing significance of these proven abilities, as mankind looks to the future.
It has been estimated that up to 70% of soils across Europe are unhealthy. In other words, one facet or another of their functionality has been compromised.
Legislation and government policy
This has generated a major call to action in terms of the legislative landscape and in terms of research and innovation.
There is currently a major commitment at an international level to address the links between soil health and food.
According to O’Sullivan, the commitment to international research into soil health is now on a par with that dedicated to the challenge of cancer.
O’Sullivan commented: “We now have longer-term goals in place, in terms of the European Green Deal. This includes the securing of climate neutrality, and the role of soil management techniques in helping to achieve this objective has already been recognised.
“We also have a new soil strategy. This means that by 2030, we are expected to have 70% of our soils in a healthy state.
“These are pan-European targets. In relative terms, Irish soils are comparatively healthy, compared to our European counterparts,” she added.
“However, it’s important to realise that soil health is very context orientated. Irish soils face a number of specific threats, which are different e.g., to those in the Mediterranean.”
Actively managing soils
O’Sullivan pointed out that soil erosion is a major issue in southern Europe. Meanwhile, soil compaction is a key challenge in Ireland – brought on, for the most part, by the continuing use of heavy machinery.
Compaction can lead to increased surface run-off, flooding, erosion and transport of nutrients and agrochemicals to open water.
Compacted soils impede root development which can reduce yields. Along with reduced plant growth, poor aeration induces the loss of soil nitrogen and produces GHGs through de-nitrification in anaerobic sites.
The Teagasc representative also highlighted salinisation and sealing as other factors that compromise soil functionality in Ireland.
“Climate change will change the context within which we manage our soils. As a consequence, problems that we have not had to deal with in the past could arise in the future, unless we take the steps to stop them from arising in the first place,” she said.
“But there are also opportunities to be availed of in terms of soil management. Getting our organic manures balanced for fertility purposes.
“This is one of the biggest challenges faced by Irish agriculture. But this is an issue that can be addressed.”
O’Sullivan pointed to the enhanced role for diversified grass swards into the future. Other mitigating factors that will maintain soil health include minimum tillage and cover crops.